I know there are other threads about fuses but thought I'd post a new one.
1990 F-L was out in heavy rain most of the weekend. Weather brightened up on Sunday afternoon so checked her over, she started OK (eventually) and ran for ten minutes or so.

Today on the way to work she just died. Felt like an electrical problem so I checked the fuses. The second fuse (from the front) - 10A - had blown. (What circuit is that for?) Fitted a new fuse, it blew as soon as I turned the key.

So I disconnected the cables from the battery that were for my accessories (heated grips etc) leaving just the two bike cables. Started OK but only got a hundred yards down the road before it blew again. Called the AA man, he couldn't fix it so (three hours later) was taken home.

Tonight, had another go at fixing. AA man had said possibly a problem with the ignition barrel, so I flooded it with WD40 via the key slot. Turned the key and the main 30A fuse blew.

That 4-pin connector has been melted some time in the past and one of the female ones in the upper plastic 4-pin connector looked mighty close to another so I took it out and wired it separately. This didn't help, the fuse blows every time I turn the key.

Recently I've had a bit of trouble with the starter button. Sometimes doesn't seem to push all the way in so I took feeds off the wires to allow me to 'jump-start' without using the starter button. The AA man disconnected my extra cables but it didn't help. Could the starter button be shorting (though the fuses blow as oon as you turn the key)?

Or is it down to the heavy rain?

Thanks folks.

 

sorry to hear about you trouble. did you figure out what that fuse is for? usually its labeled on a cover on in the manual. to help isolate your short, try unplugging the connectors one at a time until the fuse stops blowing. also look around the harness for places where it can touch something metal and could be worn through.

 

I'd be thinking the AA man was on the money - sounds like a dicky switch

 

Worked on my blowing fuses as follows:
1. removed the melted red connector from the loom to the starter relay, replaced with four separate cables, now the main fuse doesn't blow!
2. cut the three wires from the starter button, turned the key to ON, the red fuse that used to blow, didn't blow this time (this is the fuse for the ignition circuit) - so far so good
3. held a piece of wire between two of the cut ignition wires to bypass the starter button - the engine turned over but didn't fire (presume one of the cut wires was like pressing the kill switch) - so far so good - thought I'd fixed it
4. turned the key to OFF, jiggled the cut cables around a bit as I wanted to attach my piece of wire to one of the two cables I joined in step 3
5. turned the key to ON - guess what - the red fuse blew - several times
6. removed the ignition barrel, stripped it right down to the white plastic core - a bit of blue-green powder around the solder at the end of the main red cable but no chafed cables etc - but no grease anywhere (should there be?)
7. turning the white plastic core anti-clockwise activated the parking light OK, and the red fuse didn't blow, but turning it clockwise to ON blew the fuse again

Anyone got any suggestions or is it going to be a long haul looking for shorts? If there is a short, as it's the ignition circuit fuse that always blows, does this narrow it down?

Cheers

 

Sorry I cant offer any help but I had the exact same problem. Keep blowing the second 10A (ignition) and eventually blew the main. If I get it figured out I will let you know. Good luck.

 

Last night I jiggled the wires around, sprayed in some more WD40, by-passed the starter button, and I couldn't get the fuse to blow! In fact the bike started first time every time even without choke! Better than ever!
Then I re-connected the three wires from the starter button, fully expecting it to blow the fuse straight away, but no sign of any fuse blowing.

Beats me.

I'll run her for a while on the centre stand at the weekend to see if the fuses stay intact.

So it must be a kinked wire, or a chafing wire - or perhaps the damp and rainwater that got in have gone. I did notice that the vinyl sock that encloses the cables under the fuse box was torn, so maybe water got in there.

Anyone know the best way to waterproof bare connectors? Is bathroom silicone sealant OK? I need to protect the four separate cables that have replaced the block connector at the main fuse.

pmcg, try jiggling the wires and lots of WD40!

 

AHHH yes the scientific approach. Glad its working again.

 

Have you checked where the wires go into the case for the ALT?

 

Er, I've a bit of a mental block - what is the ALT?

 

i think he means alternator

Rob